Economizer for furnaces



Aug. 27, 1940. p BRACE I 2,212,976

ECONOMIZER FOR FURNACES Filed Feb. 2, 1938 Q g E 5. L": 59.

INVENTOR. KEMPER f? BFEHCE ATTORNEYS.

Patented Aug. 27, 1940 ECONOMIZER FOR FURNACES Kemper P. Brace, South Bend, Ind., assignor to International Engineering Corporation, Chicago, 111., a corporation of Illinois Application February 2, 1938, Serial No. 188,273

15 Claims.-

Thls invention relates to a heat economizer for thermostatically-controlled furnaces and has particular advantages when used in conjunction with an oil burner of the type disclosed and 5 claimed in my Patent 2,174,818, issued Oct. 3,

1939. The principal object of the invention is to prevent rapid cooling of the fire box in such a, furnace when the thermostat has turned off the i burner.

Another object is to promote more rapid ignition and development. of the flame in a burner of the type shown in the above-identified application.

ll Still another object is to promote the burning off of carbon from the vaporizing elements of the burners shown in the said application.

I prefer to accomplish these objects by providing means for breaking the draft to the furnace comprising an opening in the smoke pipe of the furnace between the furnace and the chimney which is normally closed by a damper, and by providing thermostatic means for opening the damper to break the draft shortly after the burner is shut oil and for closing the damper to bring the full draft to the furnace only after the burner has gotten a good start.

The first and third objects are accomplished by breaking the draft when the burner is shut off, because this prevents the usual rapid flow of cold air through the furnace which cools it quickly and which also cools the vaporizer element so quickly that the carbon does not burn 011.

The second object is accomplished by preventing the establishment of full draft, with its consequent cooling eifect at the burner, until the vaporizer element has become heated enough to vaporize the full amount of oil fed to it.

The above and other objects and desirable particular constructions and arrangements of parts will become apparent upon reference to the following detailed description of one embodiment of my invention shown in the accompanying drawing, in which:

Figure 1 is a side elevational view with parts broken away in section of a furnace embodying my invention; and

Figure 2 is a sectional view of a portion of the furnace smoke pipe showing my novel economizer installed therein.

In Figure 1 there is shown a furnace I0 having a fire box or combustion chamber I2 in which is installed an oil burner l4 of the type described and claimed in my above-identified copending 5 application. This oil burner has a vaporizer element l6 of porous refractory material and the burner is preferably controlled by a thermostat, such as [8, installed in the space to be heated by the furnace and adapted to turn the burner on and off in accordance with the fall and rise of 5 the temperature of the air in said space.

The usual smoke pipe 20 for conducting away the gases of combustion extends from the firebox l2 of the furnace ID in a generally horizontal direction to a chimney 22 or corresponding device. My novel economizer 24 is installed in a short T 26 extending downwardly from the smoke pipe 20 and opening to the atmosphere.

It comprises a ring 28 secured in the end of the T 26 having tiltably mounted therein, on a pivot 30, a damper 32 the weight of which is slightly unbalanced in the direction to close the damper, and the area of which is disposedin unbalanced relation relative to the pivot 30 so that excessive suction in the smoke pipe will open 20 the damper. This construction enables the damper to act as an automatic draft regulator as well as an economizer.

A bracket 34 is secured to the ring 28 and extends toward "the smoke pipe 20. At its end is secured one end of a bimetallic leaf or element 36 which extends generally parallel to the smoke pipe 20. Also secured near the end of the bracket 34 by means of a 'hinge 36 is a carrier lever 38 which generally parallels the bimetallic element for a portion of its length and is then ofiset therefrom a substantial distance. Pivotally secured to the free end of bimetallic element 36 is a plunger member 40 telescopically received by a socket member 42 pivotally mounted on the free end of the carrier lever 38. The plunger and socket 42 are frictionally secured together by a friction shoe 44 slidably mounted in a transverse bore 46 of the socket 42 and urged into frictional engagement with the plunger by a, spring 40 48 abutting against an adjustment screw 50.

The socket member 42 is positioned just to one side of the damper pivot 30 so that if it moves downwardly it will engage and open the damper.

The bracket 34 is formed with a projecting finger 52 which acts as a stop member for the carrier lever 38 permitting it. to swing upwardly only enough to raise the socket member 42 clear of the damper to close it. The bracket 34 may also be formed with a projection 54 to limit the opening movement of the damper 32.

In operation, assuming that the furnace is cold, the parts of my economizer will occupy the positions shown in Figure 2 with the damper 32. open. Now, if the thermostat starts the 86 burner; it will have very little draft and consequently will rapidly heat the vaporizer element l6 and spread the flame thereover until the full oil feed is being vaporized and burned.

As soon as this occurs, the temperature of the gases in the smoke pipe 20 begins to increase, whereupon the bimetallic element bends upwardly, lifting the plunger 40, and also lifting the socket member 42 by means of the frictional connection 44-50 so that the damper 32 is permitted to close and the full draft of the chimney 22 is transmitted to the fire box [2 and burner l4.

When the socket 42 is fully lifted from the damper 32 (requiring an increase of temperature of the flue gases of from 50 to 100") the carrier lever 38 engages the finger 52 of the bracket 34 and can move no further. As the temperature of the flue gases continues to increase causing the bimetallic element to bend further upwardly the plunger 40 moves out of the socket member 42 against the resistance of the friction connection -50.

Now when the thermostat turns the burner off and the flue gases begin to cool, the bimetallic element begins to bend downward, moving with it the plunger 40 and socket 42 and immediately opening the damper 32 to break the draft. This should occur on a fall of temperature of from 50 to 100. When the damper 32 is fully open and in engagement with the stop 54 the plunger 40 is again forced into the socket 42 until, when the bimetallic element is thoroughly cooled off, all the elements again occupy the positions shown in Figure 2.

It will be noted that by means'of the frictional interconnection of the socket 42 and the plunger 40, my novel economizer works on changes in temperature to give the highly desirable results set forth in the objects of the invention.

While only one embodiment of my invention has been described in detail, it is not my intention to be limited to that embodiment or otherwise than by the terms of the appended claims.

What is claimed is:

1. An economizer for a furnace having a smoke pipe, a burner, and a thermostat which turns the burner on and off'at intervals, comprising an opening in the smoke pipe, a damper in said opening, thermostatic means for opening said damper when the temperature of the flue gases in the smoke pipe decreases and for closing said damper when the temperature of the flue gases in said smoke pipe increases.

2. An economizer for a furnace having a bumer and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means.

3. An economizer for a furnace having a bumer and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said damper being constructed and arranged to open automatically at any time the draft from said firstnamed means becomes excessive.

4. An economizer for a furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for ing the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and 2 for closing said damper on a decrease of the temperature of the gases in said means, said damper having a pivot and having unequal areas disposed on opposite sides of said pivot, the larger of said areas being the one which moves inwardly toward said first-named means when the damper is opened.

6. An economizer for a furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said thermostatic means comprising a bimetallic element fixed at one end and having means at its free end engageable with said damper to open it.

'7. An economizer for a furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said thermostatic means comprising a bimetallic element fixed at one end and having means at its free end engageable with said damper to open it, said lastnamed means comprising separable elements, one of which has a limited range of movement.

8. An economizer for a furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said thermostatic means comprising means engageable with said damper to open and close it, means for restricting the movement of said last-named means, and a bimetallic element frictionally engaged with said last-named means.

9. An economizer for a. furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said damper having a pivot and having unequal weights on opposite sides of said pivot whereby it is closed by gravity and having unequal areas on opposite sides of said pivot whereby it is automatically opened by excessive draft, and said thermostatic means comprising a member engageable with said damper to open it and removable from said damper to permit it to close, means limiting the movement of said member, an element frictionally engaged with said member, and a bimetallic element fixed at one end and secured to said element at its other end.

10. An economizer for a furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening, in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said damper having a pivot and having unequal weights on opposite sides of said pivot whereby it is closed by gravity, and said thermostatic means comprising, a member engageable with said damper to open it and removable from said damper to permit it to close, means limiting the movement of said member, an element frictionally engaged with said member, and a bimetallic element fixed at one end and secured to said element at its other end.

119111 a furnace having a burner and a thermostat for turning the burner on and off, means for creating a draft in said furnace, and means responsive to the temperature of the gases of combustion for breaking said draft when the gases of combustion from said furnace decrease in temperature and for reestablishing said draft when the gases of combustion from said furnace increase in temperature, said draft breaking means including an element responsive to the pressure in the draft creating means and operable to break the draft if it becomes excessive.

12. In a furnace having a burner and a thermostat for turning the burner on and 011', means for creating a draft in said furnace, and means responsive to the temperature of the gases of combustion for breaking said draft shortly after the burner is turned off and for re-establishing said draft shortly after the burner isturned on, said draft breaking means including an element responsive to the pressure in the draft creating means and operable to break the draft if it becomes excessive.

13. An economizer for a furnace having a burner and a thermostat for turning said burner on and oil at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said damper being unbalanced by gravity toward its closed position and unbalanced in the area affected by said draft toward its open position.

14. An economizer for a furnace having a burner and a thermostat for turningsaid burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for-closing said damper on an increase of the temperature of the gases in said means, said damper being unbalanced by gravity toward its closed positionand unbalanced in the area affected by said draft toward its open position, and said thermostatic means being constructed and arranged to act positively to open said damper and to permit it to close by its unbalanced weight. 15. An economizer for a furnace having a burner and a thermostat for turning said burner on and off at intervals, comprising means for discharging the heated gases from the furnace normally creating a draft on said furnace, means for breaking the draft comprising an opening in said means provided with a damper, and thermostatic means for opening said damper on a decrease of the temperature of the gases in said means and for closing said damper on an increase of the temperature of the gases in said means, said damper being unbalanced by gravity toward its closed position and said thermostatic means being constructed and arranged to act positively to open said damper and to permit it to close by its unbalanced weight.

KEMPER P. BRACE. 

